The invention relates generally to propellers and partially to marine propellers.
In the past, it has been known to construct marine propellers with inner and outer hubs or sleeves or bushings which were bonded to an intervening annulus of rubber or other like material. One such prior construction is shown in the Strang U.S. Pat. No. 3,356,151, issued Dec. 5, 1967.
The above-identified Strang patent, as well as the Conover U.S. Pat. No. 3,113,625, the Wolff U.S. Pat. No. 2,543,396, and the Knoth U.S. Pat. No. 3,563,670, disclose a rubber annulus which is under radial compression in order to afford torque transmission while also affording rotary slippage relative to a hub in the event of an overload condition. The radial compression is exerted through forces applied by concentric hubs or sleeves or bushings located radially inwardly and outwardly of the annulus. Such radially applied forces provide frictional restraint to rotary slippage under normal torque transmission conditions. However, such radial forces also preclude axial separation in the field between the relatively rotatable hub and annulus.
Attention is also directed to the following U.S. Pat. Nos.:
1,402,463 PA1 3,748,061 PA1 5,244,348 PA1 5,252,028 PA1 5,322,416